The proposed study will use the extinction/ reinstatement model to examine acute and chronic effects of dopamine (DA) D1 receptor agonists on cocaine-seeking behavior in rats the rats will be trained to self- administer cocaine for at least 15 days. Acute and chronic treatment effects of the DA D1 receptor partial agonist SKF-38393 (experiment 1) and the full agonist SKF-81297 (experiment 2) on cocaine-seeking behavior will be measured. The behavior will be assessed during two test phases1) reinstatement of cocaine-seeking behavior by response- contingent presentation cues previously paired with cocaine infusions, and 2) reinstatement of extinguished cocaine-seeking behavior by cocaine priming infusions. Experiment 3 will examine the specificity of the above effects by comparing the effects of a D1 receptor agonist on cocaine- versus sucrose-seeking behavior in separate groups of rats that have been previously trained to press a lever for these respective reinforcers. It is predicted that partial D1 agonists will selectively attenuate cocaine- seeking behavior while the full D1 agonist will specifically attenuate cocaine-seeking behavior. These experiment will provide information relevant to the development of a pharmacotherapy for cocaine dependence.